Cylinder construction for an internal combustion engine



J. DOLZA 2,851,021)

' CYLINDER CONSTRUCTION FOR AN INTERNAL COMBUSTION ENGINE Sept. 9-, 1958 Filed June 25, 1956 ,Y I, x Wm M w WI W i mnw o y 1 M m I c I flfl/ AZ Y J v x I f z i ./w u N b. X y NW 41 VA 5 I I 6 2 f United CONSTRUCTIUN FOR AN INTERNAL CONEUSTIUN ENGINE Application June 25, 1956, Serial No. 593,712

9 Claims. (Cl. 123-41.69)

CYLINDER This invention relates to an internal combustion engine and, more particularly, to a cylinder construction for an internal combustion engine of the type having one or more separate cylinders individually secured to the engine crankcase.

Among the principal objects of the invention are to provide an improved cylinder construction for such an engine, to provide an improved means for mounting such a cylinder construction, and to provide an improved means for effecting a seal between a cylinder head, and a cylinder sleeve.

Further objects of the invention are to provide a cylinder for a high compression engine which is of relatively light construction and to provide such a cylinder construction for an air-cooled, compression-ignition engine.

The combined means for accomplishing the foregoing and'other objects, features and advantages of the invention will be more thoroughly understood from the following description of a preferred embodiment thereof having reference to the attached drawing, in which:

Figure l is a longitudinal sectional view of an engine cylinder embodying the invention; and

Figure 2 is an elevational view taken substantially on.

the line 22 of Figure 1 and having certain elements thereof removed.

Referring more particularly to the drawing, Figure 1 shows a cylinder assembly for a loop-scavenged, twocycle, air-cooled, compression-ignition, fuel-injection, internal combustiton engine. The cylinder assembly includes a cylinder sleeve or barrel 10, the lower end of which is mounted in an opening provided in a crankcase 12., The sleeve is of a suitable material such as cast iron and is closed at its upper end by a cylinder head 16 to form an expansible chamber with a piston 14 reciprocably mounted therein. The piston 14 is connectible through a wrist pin 17 and a connecting rod 18 to the engine crankshaft of the engine, not shown. A plurality of axially-spaced compression and oil control rings are mounted in circumferential grooves provided therefor in the piston skirt as indicated at 19.

A plurality of scavenging and charging air inlet ports 20 and a plurality of exhaust ports 22 are formed on opposite sides of the cylinder sleeve in a circumferential belt intermediate its ends, and are controlled by the reciprocation of the piston 14. The ports 20 and 22 mate with air inlet and exhaust passages 24 and 26, respectively, which are provided in an annular mufi 28 interposed between an annular boss 30 formed circumferentially of the cylinder barrel and the crankcase 12. The air inlet passages 24 are connectible through air box passages 32 provided in the crankcase to an engine driven or exhaust turbine driven compressor, not shown, and the exhaust passage portion of the muff 28 is connectible to a suitable exhaust manifold system, also not shown. An annular cooling mufi 34 embraces the cylinder barrel above the muff 28 and is secured to the barrel in heat conducting contact. The muff 34 serves to reinforce the upper end of the cylinder barrel and has cooling means ICC . 2 associated therewith in the form ofva plurality of cooling fins 36. Both the muffs 28 and 34 may be cast of a suitable material, such as aluminum or cast iron, but both need not be of the same material.

In the embodiment shown, the cylinder head 16 mounts a fuel injector 43 having a multiple hole nozle tip 44 which projects axially into -a combustion chamber C which is formed between a cylinder head carried heat resistant and insulated insert 45 and a similar piston carried insert 46. The combustion chamber inserts 45 and 46 are preferably of the type shown and described in copending United States patent application.

Serial No. 593,466, filed June 25, ,1956, in the name of John Dolza, entitled Combustion Chamber for Internal Combustion Engine. The cylinder head 16 is preferably cast of a material such as aluminum and has a circumferential lip 37 embracing the end of the cylinder sleeve, a plurality of cooling fins 38, and a plurality of radially-spaced, outwardldy-extending lugs or bosses 39 formed on its outer surface.

The head is secured in pressure sealing relation with the upper end face 41 of the cylinder sleeve by a plurality of stud bolts 40. These bolts extend through axially-aligned holes 29 and 35 provided in the muffs 28 and 34, respectively, between the crankcase and the radially-spaced bosses 39 formed on the cylinder head.

vertical vector F is required to insure the maintenance of pressure sealing contact between'the cylinder sleeveand the head under all operative conditions. This force is necessarily equal for each of the bolts and the summation of these forces represents the total clamping force acting and reacting between the annular mating surfaces of the cylinder sleeve and the head. The reaction of the cylinder sleeve opposing the clamping force of each bolt is indicated by the vertical vector P and acts through an arcuate radial sector which is indicated by the broken line r passing subtsantially through the peripheral edge of the end face 41. It will be noted that the end face 41 of the cylinder sleeve is chamfered as indicated at 42.

In accordance with one particular aspect of the invention, the bolts 40 are inclined radially inwardly toward the cylinder head and toward the axis of the piston and the cylinder. Inthe embodiment shown, this inclination of the bolts is at an angle of approximately seven or eight degrees from the vertical as seen in Figure 1. This inclination reduces the moment arm through which the tightening force applied to each bolt acts relative to the contacting surfaces of the cylinder sleeve and head. Since the line of action r of the sleeve reaction F passes through the reacting surfaces of the bolt head and the adjacent boss 39, it will be seen that the bending moment acting on the head due to the vertical component P of the bolt tightening force is at least substantially eliminated. Thus distortion of the cylinder head and the sleeve due to cylinder head bolt loading is minimized with this construction and as a result these components need not be designed with the rigidity and weight which would otherwise be required, particularly in the cylinder head. Consequently, the entire engine may be of a relatively lighter construction. This head bolt ar-r I claim:

1. A cylinder assembly for an engine including a crankcase, a cylinder having one end thereof mounted in said crankcase, a head membe'nin pressure sealing contact with th'e opposite end of said cylinder, a piston reciprocably mounted insaid cylinder and defining an expansible pressure chamber therewith, and means for securing said cylinder assembly to said crankcase and for maintining said head in pressure sealing contact with said cylinder, said means including a pluralityof radially-spaced bolts extending between said head and said crankcase, said bolts being inclined radially inwardly toward said head from said crankcase thereby minimizing the bending moments acting on said head due to the tightening forces applied to said bolts.

2. An internal combustion engine comprising, in combination, a crankcase having an openingthereima cylinder sleeve having one end thereof mounted in said crankcase opening, a head member having cooling'means associated therewith and closing the opposite end of said sleeve, a piston reciprocably mounted in said sleeve and defining an expansible chamber with said closed end of said sleeve, an annular member having cooling means associated therewith embracing and reinforcing said sleeve-adjacent said closed end, and a pluralityo'flbolts extending between said head and said crankcase through said annular member to secure said cylinder assembly to said crankcase and to maintain said head in pressure sealing contact with said sleeve, said bolts being inclined radially inwardly toward said head from said crankcase thereby minimizing the bending moments acting on said head due to the tightening forces applied to said bolts.

3. A cylinder assembly for a two-cycle internal combustion engine comprising, in combination, a crankcase having an opening therein, a. cylinder member having one end thereof mounted in said crankcase opening, a head member in pressure sealing contact with andrclosing the opposite end of said cylinder member, said head having cooling means associated therewith including a plurality of head reinforcing and cooling fins, a piston reciprocably mounted in said sleeve and defining anexpansible chamber with said closed end of said cylinder member, said cylinder member having a plurality of air inlet and exhaust ports intermediate its ends and controllable by said piston, an annular member embracing said cylinder member and having a plurality of air supply and exhaust passages therein alignable with said air and exhaust ports, a second annular member embracing said cylinder member adjacent said opposite closed end, said second annular member having cooling means associated therewith including a plurality of reinforcing and cooling fins, and means for securingsaid members to said crankcase and maintaining said head in pressure sealing contact with said cylinder member,

said securing means including a plurality of radiallyspaced bolts extending between said head and said crankcase through said annular member, said bolts being inclined radially inwardly toward said head from said crankcase thereby minimizing the bending moments acting on said head due to the tightening forces applied through said bolts.

4. In a two-cycle, air-cooled internal combustion engine, the combination comprising a crankcase, a cylinder sleeve having one end thereof mounted in an opening provided in said crankcase,a head member closing the opposite end of said sleeve and having a plurality of head reinforcing and cooling fins formed thereon, an annular member embracing said sleeve adjacent said closed end and having a plurality of'reinforcing'and cooling fins formed thereon, a piston reciprocably mounted in saidsleeve and defining an expansible chamber with said closed end of said sleeve, said sleeve having a plurality of ports therein intermediate its ends and controllable by said piston, a second annular member embracing said sleeve andhaving a plurality of passages therein alignable with said ports, and a plurality of radially-spaced bolts extending between said head and said crankcase through said annular member for securing said cylinder assembly to said crankcase and maintaining said head in pressure sealing contact with said sleeve, said bolts acting on said head member substantially in line with an axial projection of the annular pressure sealing contact between said members thereby minimizing the bending moments acting on said head due to the tightening forces applied bysaid means.

5. In an engine, a cylinder construction comprising, in combination, a cylinder, a head member closing one end of said cylinder, a support member telescopically embracing the opposite end of said cylinder, a radiallyextending shoulder carried by said cylinder and adapted to engagesaid support member, a means for clamping said cylinder between said head member and said support member thereby urging said shoulder into engagement with said support member and maintaining said head member in annular pressure sealingcontact with said one end of said cylinder, said clamping means acting on said head member in spaced relation to and in line with the annular pressuresealing contact between said head member and said cylinder thereby minimizing the bending moments acting on said head due to the clampingforces applied through said clampingmeans.

6. In the combination as set forth in claim 5, said clamping means including a plurality of radially-spaced bolts extending between said head member and said support member, said bolts being inclined radially inwardly toward'said head'member and engaging said head member in substantially axially-spaced alignment from said annular pressure sealing contact.

7. In an air-cooled, compression-ignition, internal combustion engine, the combination comprising a crankcase, a cylinder of a relatively heat resistant metal having one end thereof mounted in an.opening provided in said crankcase, a head member of a relatively light metal closing the opposite end of said cylinder, said head having a circumferential lip embracing said opposite end and having a plurality of head reinforcing and cooling fins, an annular member of a relatively light metal embracing and reinforcing said'cylinder adjacent said opposite end, said annular member 'having'a plurality of cooling fins radiating therefrom, a piston of a relatively light metal reciprocably mounted in said sleeve and defining an cxpansible chamber with said closed end of said sleeve, said piston and said head member each' carrying an insert of relatively high heat resistant material, said inserts defining a combustion chamber .therebetween, said inserts being adapted to isolate said headand said piston from the heat of 'the main combustion occurring therein, and means for securing said cylinder assemblyto said crankcase and maintaining said head in pressure sealng contact with said sleeve.

8. In the combination as set forth in claim 7, said securing means including a plurality of radially-spaced bolts extending between said head and said crankcase.

9. In the combination as set forth in claim 7, said securing means including a plurality of radially-spaced bolts extending between said head and said crankcase, said bolts being inclined radially inwardly toward said head from said crankcase thereby minimizing the bending moments acting on said head due to the tightening forces applied to said bolts.

References Cited in the file of this patent UNITED STATES PATENTS 2,066,580 Severin et al. Jan. 5, 1937 2,714,373 Spannhake Aug. 2, 1955 FOREIGN PATENTS 261,318 Great Britain Nov. 18, 1926 

